Pemetrexed is approved as a monotherapy for second line and maintenance treatment of non-squamous non-small cell lung cancer. (NSCLC) Pemetrexed based platinum doublet chemotherapy followed by maintenance pemetrexed chemotherapy is the current standard of care for lung adenocarcinoma with no actionable mutations. However, many patients receiving such cytotoxic chemotherapy do not receive clinical benefit from the therapy.
Response rate to pemetrexed based regimes as initial treatment is approximately 24-31%, while the disease control rate is approximately 60%. Response rate to pemetrexed is approximately 11.5% in the second line setting. Currently no clinically validated predictive marker is available to identify which patients will benefit from pemetrexed treatment. Thus, since pemetrexed treatment is expensive and may have significant side effects, it would be beneficial to more accurately determine which patients are more likely to benefit from pemetrexed treatment.